50 MARCUS M. HARTOG. 
matogeny goes on by budding as in mode (6). The spermatozoa 
become free and leave behind a uninucleated blastophore, 
which is not known to be capable of further growth or division. 
We may fairly connect this peculiarity with the attachment of 
the spermatogonia in most cases, the nucleated blastophore 
serving as an active intermediary for the exchanges between 
the wall of the tube and the developing spermatozoa. And 
this is a character of adaptation, of no morphological, and of 
minor physiological importance.! I annex a schema (Fig. 8) of 
a spermatogonium of this kind, in which four divisions are 
supposed to have occurred. Owing to the fate of one of the 
BENS 4 
NO 
yo N! 241 = 8 spermatozoa. 
x 
Wa \neZ N* 
mae > Ni 
Aw, me 
nucleated blastophore. 
Fie. $8.—Schema of spermatogeny, with formation of nucleated blastophore ; 
Grantia type. 
first two nuclei the number of spermatozoa formed at the 
mth bipartition of the nucleus is only 2"~1, instead of 2”, 
i.e. only half the normal number. 
2. Oogeny. 
The Metazoan oogonium, the “ ovarian egg” or ‘‘ ovum” of 
authors, is peculiar in attaining an enormous size, owing to its 
power of storing up reserve supplies in the form of unorganised 
yolk-granules to supply the metabolism of the future embryo; 
and, correlated with this, it usually possesses an immense 
‘ Our interpretation of the nucleated blastophore, as a nutritive organ 
rather than as an excretion, is confirmed by the fact that the numerous 
broods of Rat spermatozoa, formed by mode (a), contract a union with a basal 
cell; and this syncytium is undistinguishable from the apocytium of the 
spermatocytes and nucleated blastophore in mode (c). 
